Polycarbonate compositions, methods of manufacture, and methods of use
A polycarbonate composition includes: a continuous polycarbonate phase; discontinuous first domains distributed in the continuous phase, and comprising a core-shell silicone-(meth)acrylate impact modifier comprising a silicone elastomer core and a (meth)acrylate copolymer shell, wherein the first domains have an aspect ratio of at least 1.7, preferably at least 1.8; and discontinuous second domains distributed in the continuous phase, and comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second domains have an aspect ratio of at least 3, preferably at least 4, and a domain size of 6400 square nanometers or less, more preferably 5700 square nanometers or less. Optionally, the polycarbonate composition includes: a polycarbonate; a brominated polycarbonate different from the polycarbonate; a poly(carbonate-siloxane) comprising 30 to 70 weight percent of siloxane blocks; a core-shell silicone-(meth)acrylate impact modifier comprising a silicone elastomer core and an (meth)acrylate copolymer shell; and an alkenyl aromatic-olefin block copolymer impact modifier.
1. A polycarbonate composition comprising:
a continuous phase comprising a polycarbonate component;
discontinuous first domains distributed in the continuous phase, and comprising a core-shell silicone-(meth)acrylate impact modifier comprising a silicone elastomer core and a (meth)acrylate copolymer shell, wherein the first domains have an aspect ratio of at least 1.7; and
discontinuous second domains distributed in the continuous phase, and comprising an alkenyl aromatic-olefin block copolymer impact modifier, wherein the second domains have an aspect ratio of at least 3, and a domain size of 6400 square nanometers or less;
each as determined by scanning transmission electron microscopy of an outer surface of a molded sample, within 10 micrometers of the outer surface.
2. The composition of 1 , wherein
a molded sample of the composition does not show tracking after at least 50 drops of an aqueous 0.1% ammonium chloride solution measured at 600 V as determined by ASTM D-3638-85; and
a molded sample of the composition having a thickness of 3.2 millimeters has at least one of the following properties:
a notched Izod impact strength of greater than 500 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −30° C.;
a notched Izod impact strength of greater than 500 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −40° C.
3. The composition of claim 1 , comprising:
60 to 80 weight percent of a polycarbonate;
10 to 30 weight percent of a brominated polycarbonate different from the polycarbonate;
0.5 to 5 weight percent of a poly(carbonate-siloxane) comprising 30 to 70 weight percent of siloxane blocks;
1 to 10 weight percent of the core-shell silicone-(meth)acrylate impact modifier comprising a silicone elastomer core and a (meth)acrylate copolymer shell; and
0.5 to 5 weight percent of the alkenyl aromatic-olefin block copolymer impact modifier;
wherein the weight percent of each component is based on the total weight of the composition, which totals 100 weight percent.
4. The composition of claim 1 , further comprising 0.01 to 2 weight percent of an anti-drip agent.
5. The composition of claim 1 , comprising 2 to 3 weight percent of an alkenyl aromatic-olefin block copolymer impact modifier, based on the total weight of the composition.
6. The composition of claim 1 , having at least one of the following properties:
a molded sample of the composition retains at least 90 percent Mw after 336 hours in a hydrolytic chamber at 85° C. and 85 percent relative humidity;
a molded sample of the composition retains greater than 85 percent Mw after 692 hours in a hydrolytic chamber at 85° C. and 85 percent relative humidity; or
a molded sample of the composition retains greater than 75 percent Mw after 1000 hours in a hydrolytic chamber at 85° C. and 85% relative humidity.
7. The composition of claim 1 , having at least one of the following properties:
a molded sample of the composition retains at least 80 percent notched Izod impact strength measured at 23° C. according to ASTM D256 after 336 hours in a hydrolytic chamber at 85° C. and 85 percent relative humidity,
molded sample of the composition retains at least 65 percent notched Izod impact strength measured at 23° C. according to ASTM D256 after 692 hours in a hydrolytic chamber at 85° C. and 85 percent relative humidity; or
a molded sample of the composition retains at least 50 percent notched Izod impact strength measured at 23° C. according to ASTM D256 after 1000 hours in a hydrolytic chamber at 85° C. and 85 percent relative humidity.
8. The composition of claim 1 , wherein a molded sample of the composition having a thickness of 3.2 millimeters has at least one of the following properties:
a notched Izod impact strength of greater than 500 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −30° C.; or
a notched Izod impact strength of greater than 500 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −40° C.
9. The composition of claim 1 , wherein a molded sample of the composition having a thickness of 0.8 millimeters has a UL94 flame retardance rating of V0.
10. The composition of claim 1 ,
wherein the polycarbonate comprises a bisphenol A homopolycarbonate.
11. The composition of claim 1 , wherein the core-shell silicone-(meth) is a dimethylsiloxane-methyl methacrylate copolymer having a particle size of 200 to 400 nanometer or a particle size of greater than 400 nanometer.
12. The composition of claim 1 , wherein a molded sample of the composition having a thickness of 3.2 millimeters has at least one of
a notched Izod impact strength of greater than 600 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −30° C; or
a UL94 flame retardance rating of V0.
13. The composition of claim 1 , wherein the core-shell silicone-(meth) is a dimethylsiloxane-methyl methacrylate copolymer, present in an amount of 1 to 5 weight percent, based on the total weight of the composition.
14. The composition of claim 1 , comprising:
65 to 75 weight percent of a polycarbonate, wherein the polycarbonate comprises a first bisphenol A homopolycarbonate having a weight average molecular weight of 21,000 to 23,000 Daltons and a second bisphenol A homopolycarbonate having a weight average molecular weight of 29,900 to 31,000 Daltons;
15 to 25 weight percent of a brominated bisphenol A polycarbonate;
0.8 to 3 weight percent of a poly(bisphenol A carbonate-dimethylsiloxane) comprising 30 to 70 weight percent of dimethylsiloxane blocks;
3 to 5 weight percent of a core-shell dimethylsiloxane-methyl methacrylate impact modifier;
1 to 5 weight percent of a styrene-ethylene/butylene-styrene block copolymer impact modifier;
0.1 to 0.5 weight percent of a poly(tetrafluoroethylene)-encapsulated styrene-acrylonitrile; and
0.1 to 3 weight percent of a combination of a colorant, a mold release agent, a heat stabilizer, and an ultraviolet light stabilizer.
15. The composition of claim 14 , wherein a molded sample of the composition does not show tracking after at least 50 drops of an aqueous 0.1% ammonium chloride solution measured at 600 V as determined by ASTM D-3638-85;
a molded sample of the composition having a thickness of 3.2 millimeters has a notched Izod impact strength of greater than 500 Joules/meter and a ductility of 100% measured according to ASTM D256 at a temperature of −30° C.;
a molded sample of the composition having a thickness of 3.2 millimeters has a tensile strength greater than or equal to 55 megapascal determined according to ASTM D638;
a molded sample of the composition having a thickness of 3.2 millimeters has a tensile modulus of greater than or equal to 2 gigapascal determined according to ASTM method D638; and
a molded sample of the composition having a thickness of 0.8 millimeters has a UL94 flame retardance rating of V0.
16. The composition of 14 , wherein a molded sample of the composition does not show tracking after at least 50 drops of an aqueous 0.1% ammonium chloride solution measured at 600 V as determined by ASTM D-3638-85.
17. The composition of claim 14 , wherein the brominated polycarbonate comprises brominated bisphenol A having a bromine content of 24 to 27.5 weight percent, relative to the total weight of the brominated polycarbonate.
18. The composition of claim 4 , wherein the poly(bisphenol A carbonate-dimethyl siloxane) has
carbonate blocks having a glass transition temperature greater than 70° C. and siloxane blocks having a glass transition temperature of minus 130 to minus 50° C.
a weight average molecular weight of 10,000 to 100,000 Daltons;
at least 30% elongation before yield as measured by ASTM D638; and
a Shore D hardness of 5 to 20 as measured by ASTM D2240.
19. An article comprising the composition of claim 1 , wherein
the article is a molded article, a thermoformed article, an extruded film, an extruded sheet, one or more layers of a multi-layer article, a substrate for a coated article, or a substrate for a metallized article.
20. The article of claim 19 , wherein the article is a solar apparatus, an electrical junction box, an electrical connector, an electrical vehicle charger, an outdoor electrical enclosure, a smart meter enclosure, a smart grid power node, a photovoltaic frame, or a miniature circuit breaker.